Contribution to the characterization and identification of human stability with regard to safety: application to guided transport systems

Benard, V., Richard, P., Vanderhaegen, F. and Caulier, P.

This paper presents an original contribution based on the concept of human stability by identifying the associated risks as part of the safety system assessment. The difficulties to take into account human factors in safety studies are first highlighted and definitions of new ways for the integration of human factors based on the existing concepts of stability and resilience are proposed. Although the stability concept is usually defined around a sustainable equilibrium point that induces a feeling of safety control during normal operation, it appears that the stable behaviour of a human operator can lead to risk in certain situations or contexts such as hypo-vigilance, inattention and so on. The core of this paper lays the foundation of human stability for risks assessment. Here, Human stability is defined as the ability of the operator to stay in a stable operating state under specified conditions. This concept is formalized and 3 modes of stability are developed (time, frequency and sequential modes) in order to identify states and change of states of the human stability. The concept of human stability is then applied in the framework of ERTMS/ETCS and shows that sequences of Human stability states and changes of Human stability states may be precursors of risk. Finally, some perspectives highlight the interest of human stability for the definition of risk indicators to assess system safety, by considering the Human operator as a safety/security multi-criteria sensor for the supervision of human-machine systems.

Cite as: Benard, V., Richard, P., Vanderhaegen, F. and Caulier, P. (2012). Contribution to the characterization and identification of human stability with regard to safety: application to guided transport systems. In Proc. Australian System Safety Conference 2012 (ASSC 2012) Brisbane, Australia. CRPIT, 145. Cant, T. Eds., ACS. 13-20

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